Kingdom Monera & Microscopes Flashcards
First virus discovered
Tobacco mosaic virus: discovered by wendell Stanley
Characteristics that make a virus non-living
Outside a living call appear to be lifeless chemical and carry out no functions on their own
Can only reproduce inside a living cell (obligate intercellular parasite)
Occupies position between living and non-living
Viral structure
20nm-40nm
Do not contain: nucleus, inner membrane, or membrane bound organelles
Consist of: inner nucleic acid cord, outer protein coat called capsid (makes up 95% of virus and gives shape), often have lipid membrane called envelope
know how to draw
Virus shapes
- Helix
- Polyhedral
- Envelope
- Polyhedral head w/ cylindrical tail
Viral specificity
Describes how many kinds of organisms the virus is able to infect (host range)
Viruses identify host by fitting proteins on capsid with specific receptors on outside of host cell surface
Bacteriophage
Type of virus that infects bacteria cells
Ex: T4 bacteriophage
Lytic cycle
- Attachment and entrance: virus recognizes host, whole virus/nucleic acid enters
- Synthesis of protein and nucleic acid: virus takes over mechanism of replication
- Assembly: virus proteins and nucleic acids are assembled into particles
- Release: fully formed viruses burst cell and are released
- takes around 25-45 minutes
Lysogenic cycle
- Starts same as lytic cycle
- DNA becomes integrated into host cells DNA (now called prophage/provirus)
- DNA is replicated along with host cell
- Change in environment (temp, nutrients, damage…) causes cell to enter lytic cycle.
remains undetected
Non specific lines of defense
- skin
- mucous membranes
- oil and sweat glands
- gastric juice
Specific lines of defense
Immune response: antibodies are produced and bind to virus
Cells can then engulf and destroy
How viruses cause disease
How they are hard to treat
Attack cells, destroying them and thereby causing symptoms of the disease
They are active while safely inside our body and cannot be treated with antibodies, some become latent, they attack immune system, and mutate quickly
Vaccines
Are weakened or similar forms of the virus. These are injected into the person and their immune system easily fights off virus (produced antibodies)
Memory cell now recognizes virus and will fight it off before sickness is caused
Endemic
With us all the time (cold virus)
Epidemic
When a disease starts to spread rapidly
Pandemic
When a disease spreads throughout the world (small pox)
Retroviruses
Replicate nucleic acid in reverse of standard: use RNA to make DNA
Uses reverse transcriptase
- have envelope
Viroids
Tiny particles of pure RNA: causes disease in plants. There is no cure.
Prions
Are particles of proteins that cause some disease in animals: mutated gene
Prokaryotes
- do not have a nucleus
- do not have membrane bound organelles
- do have ribosomes (they differ)
- almost all smaller than smallest eukaryote
- most are single celled
- draw prokaryote*
Pili
Aid in:
- docking or sticking to surface
- exchange of DNA
Archaebacteria
- Live in extreme environments
- most species are harmless, some beneficial
- chemically distinct (cell walls, membranes, and ribosomal RNA)
- divided into 4 groups: methanogens, thermoacidophyles, chemosynthesizers, and extreme halophiles
Methanogens
- produce methane
- live in oxygen free environment
Found in: swamps, marshes, mammals - used to treat sewage and purify waste water
Thermoacidophyles
- live in extremely hot (6-250 degrees Celsius) and acidic water
Chemosynthesizers
- use inorganic compounds as an energy source
- live in deep sea hot springs formed by volcanic vents in ocean floor
Extreme halophiles
- live in extremely salty conditions such as: Great salt lake Utah, and Dead Sea.
- can grow in water 10x saltier than sea water
Eubacteria
All organisms known as bacteria
Divided into 3 groups: gram positive, gram negative, and Cyanobacteria
Gram positive bacteria
Have thick wall or protein-sugar complex that takes on purple colour during gram staining
Ex: found in yogurt, buttermilk, streptococcus
Gram negative bacteria
Have an extra layer of lipid on the outside of cell wall and appear red after staining
Ex: rhizebacteria (nitrogen fixing)
Cyanobacteria
Gram negative monerans that perform plant-like photosynthesis and release oxygen as a byproduct
- are much larger than most prokaryotes
- provide food for other organisms
Ex: thylakoids
Characteristics of bacteria
- Respiration: aerobic, anaerobic, and facultative anaerobes
- Metabolism: autotrophs, photoautotrophs, chemoautotrophs, heterotrophs, saprophytes, mutualistic
- Reproduction: binary fission, stressful environments= sexual
Gram staining
Bacteria stained with purple dye and iodine, rinsed in alcohol, then stained with red dye
Aerobic
Obligate aerobes: need oxygen to survive
Anaerobic
- Obligate anaerobes: killed by oxygen so must live in absence of it
- Facultative anaerobes: can use oxygen if it’s available
Autotrophs
Organism that produces own food
Photoautotrophs
Use energy from sun to produce it’s own food
Chemoautotrophs
Obtain energy from inorganic substances rather than sunlight
Heterotrophs
An organism that cannot produce its own food
Saprophytes: decompose dead animals
Parasites: feed on live organisms and cause disease
Mutualist: symbiotic relationship where both benefit
Binary fission
Asexual reproduction
- most monerans use this process
- chromosome replicates and cell divides creating 2 identical cells
Causes of variation in bacterial DNA
- Mutations of DNA and RNA are most important source
2. Sexual reproduction: conjugation, transduction, and transformation
Conjugation
Exchanging genetic material through cell-to-cell contact
- DNA moves from one cell to another
- are attached by pili forming cytoplasmic bridge
Transformation
Bacteria cells pick up and incorporate DNA from dead bacterial cells
- same or closely related species
Transduction
Uses a virus (T4 bacteriophage) to transfer DNA from one bacteria to another
- useful in genetic engineering
Bacterial growth phases
- Lag phase: slow initial growth, acclimate to nutrients in new habitat
- Exponential phase: bacteria multiply exponentially every couple of minutes
- Stationary phase: more and more bacteria compete for dwindling in nutrients. Division is slowing down/is stationary
- Death phase: toxic waste products build up, food is depleted, bacteria begin to die
Beneficial roles of bacteria
- Free up nitrogen soils for plants
- Break down dead organic material
- Symbiosis/mutualism: help digest food in animals
- industry: making cheese, buttermilk, yogurt
- clean up oil spills (digest petroleum)
- useful in making drugs
- experimental tools
Damaging roles of bacteria
- Disease
- destruction of host tissue
- toxins (endotoxins: released from dead bacteria) (exotoxins: released from living bacteria) - Contaminate food
Fighting bacteria
- Disinfectants
- Antiseptics
- Antibiotics
- inhibit growth or destroy bacteria
Ways disease is transmitted
- Moisture droplets in air
- Dust
- Direct contact
- Fecal contamination
- Animal bites
- Wounds
Problems with antibiotics
- Allergies
- Bacterial resistance: develops when a mutation allows bacteria to survive antibiotic
- Destruction of beneficial bacteria
-coccus
Spherical
-bacillus
Rod-shaped
-spirillum
Spiral
Diplo-
Pairs
Strepto-
Chains
Staphylo-
Clusters
Sarcina-
Cube of 8 cells
Field of views
4x: 4300 micrometers
100x: 1700 micrometers
400x 430 micrometers
In moneran diagram
Plasma membrane, cell wall, and then capsule
Plasmid
Small pieces of circular DNA
